CuO Products Research Articles

Large scale synthesis of ultrathin cupric oxide nanosheets via a rapid microwave-assisted and template-free route

A facile one-step microwave-assisted synthetic route was developed to prepare ultrathin and defect free CuO nanosheets without any surfactant. During the synthetic process, the 100 mL of water and ethanol mixed solution (1/1, v/v) containing 0.86 g of CuCl2·2H2O and 2 g of sodium hydroxide was heated by microwave irradiation at a power of 750 W for 20 min. Most of these CuO sheets possessed a length of 80–110 nm, 40–60 nm in width, and only 11 nm in thickness. The microstructure and morphologies of the CuO product were investigated in details by XRD, SEM, HRTEM, FT-IR, and XPS techniques, and it was found that the shapes of CuO were dependent on the concentrations of sodium hydroxide. The band gap of such CuO nanosheets was estimated to be 2.17 eV according to the UV–vis absorption curve. This effective microwave-assisted approach may be a promising route to prepare other transition metal oxides.

Characterisation of Cu2O/CuO thin films produced by plasma-assisted DC sputtering for solar cell application

For large-scale implementation of devices magnetron sputtering is a practical method of producing metal oxides, however sputtered copper oxides tend to form as a mixture of Cu2O, Cu4O3, and CuO, with Cu2O being particularly difficult to produce reliably in pure form. In this study, nanostructured thin films of Cu2O, Cu4O3, and CuO were prepared using a novel reactive sputtering system, based on plasma-assisted DC magnetron sputtering with deposition and plasma assisted reaction zones spatially separated enabling separate control of film oxidation. X-ray diffraction, optical spectroscopy, and Raman spectroscopy were used to characterise the physical and optical properties and it is shown that plasma-assisted DC sputtering is a suitable technique for reliable production of CuO and Cu2O films in large areas at room temperature without the necessity of further processing. The results also indicate that solar cell performance may relate positively to the presence of crystalline Cu4O3 (200) and/or Cu2O (111) over other crystalline forms of copper oxide or amorphous copper oxide thin films.

CuO hollow microspheres self-assembled with nanobars: Synthesis and their sensing properties to formaldehyde

CuO hollow microspheres were synthesized via a facile hydrothermal process. Copper nitrate trihydrate (Cu(NO3)2·3H2O) was used as copper source and cetyltrimethylammonium bromide (CTAB) was used as soft template. The morphology and crystal structure of products were systematically investigated by XRD, FESEM, TEM, FT-IR and BET. CuO hollow microspheres were identified as monoclinic structure. The hollow microspheres were assembled by a number of nanobars which were composed of smaller nanograins. The formaldehyde gas sensing properties of CuO products with different morphologies were investigated. The results indicated that the sensor based on CuO hollow microspheres exhibited high gas response, fast reversible and response, good selectivity and stability to formaldehyde gas. This is attributed to hollow structures with the largest specific surface area and an effective gas diffusion path in favor of mass transportation and gas diffusion.

3D CuO nanosheet wrapped nanofilm grown on Cu foil for high-performance non-enzymatic glucose biosensor electrode

3D binder-free CuO nanosheets wrapped nanofilms has been in situ synthesized on Cu substrate by a simple and facile procedure, with an aim of fabricating high-performance glucose sensor. The complex morphology that the nanosheet grown on Cu subtract evolved into nanofilms and eventually converged to nanowires, is benefit for the mass transport and electro-catalysis. Compared the ECSA of the CuO modified electrode to that of the bare Cu electrode, the effective surface area during the electro-catalysis of the CuO/Cu electrode is much larger. The glucose sensor based on CuO products exhibited high sensitivity (4201μAcm−2mM−1), low detection limit (0.5μmol/L) and quick response time (0.7s). And the stability and selectivity is also fantastic. According to the serum sample analysis, it transpires that the CuO/Cu sensor displayed excellent recovery compared to the concentration values measured by medial method. So this material shows great potential applications in glucose sensors.

Synthesis of CuO nanoparticles via one-pot wet-chemical method and its catalytic performance on the thermal decomposition of ammonium perchlorate

Sphere-like CuO products aggregated by numerous nanoparticles were fabricated by a low-temperature (50°C) wet chemical method using CuSO4·5H2O as precursor. The possible formation processes of CuO were investigated by a series of single-factor experiments. The CuO was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, selectedarea electron diffraction. Furthermore, the application of CuO nanoparticles on the thermal decomposition of ammonium perchlorate was studied with 2 wt % CuO nanoparticles at heating rates of 10, 15, 20, and 25°C min–1 from 35 to 500°C.

Selective functionalization of external and internal surface of MCM-41 for adsorptive desulfurization

MCM-41 was selectively functionalized with CuO on the external surface and Cu2+ coordinated by organosilanes on the internal surface. The production of CuO and removal of template were achieved in one step, which is convenient and a save of energy. Results of transmission electron microscopy indicate the presence of CuO on outer surface of MCM-41. The successful grafting of organosilanes was confirmed by 13C and 29Si nuclear magnetic resonance. The prepared M(CuO)N(Cu) shows more comprehensive desulfurization performance due to the simultaneous and independent incorporation of CuO and copper ions. Dimethyl sulfide and dimethyl disulfide are selectively adsorbed on external surface of M(CuO)N(Cu), while tert-butyl mercaptan can be adsorbed on both external and internal surface of M(CuO)N(Cu).

Synthesis of Novel Hollow Copper Oxide Micro-Flowers Assembled by Nanoparticles and Their Improved Catalytic Performances for the Synthesis of Organosilane

In this work, novel sisal-like hollow CuO micro-flowers were synthesized via a facile solvothermal reaction followed by calcination. The flower-like shells of hollow CuO are constructed by irregular petals interweaving each other, which are composed of aggregated nanoparticles with sizes of ca. 18[Formula: see text]nm. It was found that the flower-like morphology of the as-synthesized CuO products can be controlled via finely tuning the solvothermal reaction time. When used as catalysts for the synthesis of organosilane, the obtained hollow CuO micro-flowers exhibit better catalytic performances than the commercial CuO powders. Superior catalytic performances are due to the hollow and flower-like structures of the as-synthesized CuO products, which can promote the synthetic reaction for the organosilane, that is, the gas–solid contacting reaction occurred among the reaction gas, solid silicon powders and CuO catalysts. Our work will be helpful to design and develop the novel Cu-based nanocatalysts for the synthesis of organosilane.

The formation of CuO porous mesocrystal ellipsoids via tuning the oriented attachment mechanism

We report a new chemical reaction route to synthesizing CuO porous mesocrystal ellipsoids via decomposition of copper vanadium oxide under hydrothermal conditions. By finely tuning the oriented attachment growth mechanism of CuO, a porous mesocrystal structure was synthesized. Structural and morphological evolutions of the CuO product were investigated and the formation of CuO porous mesocrystal ellipsoids here was essentially determined by the amount of ammonium metavanadate. An oriented nanoparticle aggregation with tailoring of the structure, including compact mesocrystals and porous mesocrystals, could be achieved in different concentrations of reactants. The strategy of constructing the structure via an oriented attachment growth mechanism could be applied to the synthesis of other nanomaterials with complex structures.

Synthesis of various CuO nanostructures via a Na3PO4–assisted hydrothermal route in a CuSO4–NaOH aqueous system and their catalytic performances

Various CuO nanostructures, including spherical, flower-like, cross-like, leaf-like, and elliptical structures, were obtained via a sodium phosphate (Na3PO4)–assisted hydrothermal route with CuSO4 and NaOH as the copper and alkali sources, respectively. The presence of Na3PO4 is vital for the formation of various CuO nanostructures. The morphology of the CuO nanostructures is significantly influenced by the feeding concentration of the NaOH solution. The catalytic activity of the CuO products on the thermal decomposition of ammonium perchlorate (AP) was characterized by differential scanning calorimetry (DSC). Results showed that the addition of CuO nanostructures could dramatically decrease the high decomposition temperature of AP, thereby demonstrating their excellent catalytic activity for the thermal decomposition of AP.

CuO core–shell nanostructures: Precursor-mediated fabrication and visible-light induced photocatalytic degradation of organic pollutants

A facile route was developed for the large-scale preparation of core–shell CuO nanostructures based on a solvothermal route with subsequent calcination. The CuO nanostructures show core–shell shape and are composed of numerous nanoparticles with high porosity resulting from the thermal decomposition of the Cu2O precursors. A possible growth mechanism of the CuO core–shell nanostructures was proposed. The novel core–shell structure enlarges the range of absorbed light and enhances the absorption intensity of light. The as-obtained CuO core–shell nanospheres were evaluated for the degradation of hazardous organic contaminants in water such as phenol and methylene blue (MB) under visible light irradiation. Compared with other CuO products, the as-prepared CuO core–shell nanosphere possesses superior property on photocatalytic decomposition of phenol and MB. It is believed that the efficient photocatalytic property of the as-prepared CuO core–shell nanosphere is originated from its unique openly core–shell nanostructure, which is highly beneficial to the reagent diffusion, mass transportation and the light reflection and absorption inside the CuO nanostructure.

Novel perpendicularly cross-rectangular CuO architectures: Controlled synthesis, enhanced photocatalytic activity and catalytic thermal-decomposition of NH4ClO4

Novel perpendicularly cross-rectangular CuO architectures have been successfully fabricated on a large scale by a facile microwave-assisted chemical aqueous route. The as-synthesized CuO products were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM) and UV-vis absorption spectroscopy. An individual CuO microstructure is mainly assembled by two rectangle-shaped nanosheets with different sizes, which is perpendicularly intersected through the center. A possible formation mechanism of perpendicularly cross-rectangular CuO architectures was proposed based on the comparative experimental results. The prepared CuO nanoarchitectures exhibited excellent photocatalytic activity for the decolorization of Rhodamine B (RhB) under visible light irradiation. Simultaneously, the prepared CuO products, acting as an additive, also showed effective catalytic activity on the thermal decomposition of ammonium perchlorate (NH4ClO4).

Controlled synthesis of pricky CuO microspheres and their luminescent, photocatalytic properties

The controlled synthesis of copper oxide with crystal morphology of pricky microspheres has been realised with high yield by simple reaction of and NaOH in a solution phase. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and fluorescence spectrophotometer were used to characterise the products. It was shown that the pricky CuO microspheres were formed through aggregation of tiny single crystal nanothorns exhibiting tapering feature with tip size of less than several tens of nanometre. Experiments demonstrated that the morphology of CuO products was significantly influenced by reaction time and treatment temperature. Photocatalytic activity of the pricky CuO microspheres was evaluated by measuring the decomposition rate of methyl blue solution with the assistance of hydrogen peroxide under natural light. The pricky CuO microspheres show good photocatalytic efficiency on the oxidation and decomposition of the methyl blue dye.

Chemical-looping auto-thermal reforming of biomass using Cu-based oxygen carrier

Chemical-looping reforming (CLR) of biomass, which utilizes active lattice oxygen from oxygen carrier (OC), provides a novel route to convert biomass into synthesis gas. This research utilized Cu-based OC rather than commonly-used Fe- or Ni-based OC in the process. The possible advantage is the exothermic reactions between CuO and gasification products are beneficial to auto-thermal reforming of biomass in fuel reactor. Batch fluidized bed experiments with different carriers (silica sand, Fe-based or Cu-based OCs) were conducted at different temperatures. It was found that when using Cu-based OCs, the gas yield and carbon conversion efficiency increased significantly, but the gasification efficiency and low heating value decreased accordingly, which are ascribed to the high-reactivity Cu-based OCs prompt the carbon conversion and also consume more reducible gases. The presence of Cu-based OCs help reduce C2Hm and tar in syngas. Additionally, the tar content decreased with temperature increase, while C2Hm content first increased then decreased.

A facile one-step route for production of CuO, NiO, and CuO–NiO nanoparticles and comparison of their catalytic activity for ammonium perchlorate decomposition

This study demonstrates a straightforward, inexpensive, high-yield, and ecofriendly route for synthesis of sphere-like CuO, NiO, and CuO–NiO (with different molar ratios) nanoparticles (NPs) through emulsion route.

Simple and rapid preparation of CuO nanowires and their optical properties

Cu(OH)2 nanowires were prepared rapidly by the precipitation method at room temperature, using CuCl2, K2CO3 and NaOH as raw materials. Hierarchical copper oxide nanowires were obtained via a simple thermal conversion reaction of the Cu(OH)2 nanowires at 300°C for 2h. The influence of reaction conditions on morphologies of the CuO products and the reaction mechanism were studied based on series of control experiments. The crystal structure and morphologies of the products were characterized and the optical properties of the CuO nanowires were investigated by UV–vis diffuse reflection absorption spectrum and fluorescence spectrum. The results show that the hierarchical CuO nanowire is about 10–15nm in diameter and 300–500nm in length with a primary particle size of 12.4nm. The usage of K2CO3 and adequate NaOH is decisive for formation of the CuO nanowires. This preparation can be simply scaled up for a mass production.

Fate of CuO and ZnO Nano- and Microparticles in the Plant Environment

The environmental fate of metal oxide particles as a function of size was assessed by comparing the behavior of CuO or ZnO nanoparticles (NPs) to that of the corresponding microparticles (MPs) in a sand matrix, with and without wheat (Triticum aestivum L.) growth. After 14 days of incubation in the planted sand, the CuO and ZnO NPs were increased from their nominal sizes of <50 nm and <100 nm, to ~317 nm and ~483 nm, respectively. Accordingly, the negative surface charge of colloids present in aqueous extracts from the sand amended with CuO (-27.0 mV) and ZnO (-10.0 mV) NPs was reduced by the presence of plants, to -19.8 mV and -6.0 mV, respectively. The surface charge of the MPs was not influenced by plants. Plant growth increased dissolution of NPs and MPs of both metal oxides in the sand from <0.3 mg/kg to about 1.0 mg/kg for the CuO products, and from ≤0.6 mg/kg to between 1.0 and 2.2 mg/kg for the Zn products. The NP or MP products reduced wheat root length by ~60% or ~50% from control levels; CuO was more toxic than ZnO. X-ray absorption spectroscopy (XAS) analysis showed that treatments with MPs or NPs of ZnO led to similar accumulations of Zn-phosphate species in the shoots, likely from dissolution of ZnO. Exposure to CuO NPs or MPs resulted in similar XAS spectra for Cu in the shoots explained by plant accumulation of both CuO and Cu(I)-sulfur complexes. These findings demonstrate the similarities between commercial NPs and MPs of CuO or ZnO in wheat plants, with greater root toxicity correlating with smaller particle size. Factors from the sand and the plant modified the aggregation or dissolution of both types of particles, thus, influencing their environmental fates.

One-step self-assembled synthesis of CuO with tunable hierarchical structures and their electrocatalytic properties for nitrite oxidation in aqueous media

Controlled synthesis of CuO with various hierarchical structures consisting of self-organized nanoparticles is realized by using n-octylamine (OLA) as a structure inducing agent via a facile hydrothermal synthetic method. The growth and assemblage of CuO can be finely tuned by selecting the preparative parameters. In particular, it is found that the degree of the hierarchical organization can be modulated by simply changing the amount of the n-octylamine and CuO nanoparticles exhibit self-assembled two-dimensional (2D) sheet-like, three-dimensional (3D) disk-like and bowknot-like architectures, respectively. In the present case, OLA serves as a capping surfactant that can modulate growth of CuO nanocrystals via hydrophobic forces between the OLA molecules. CuO nanoparticles can be self-assembled into different complex architectures depending on the strength of hydrophobic forces. Hierarchical sphere-like CuO assembled from nanorods can also be easily fabricated by adjusting the starting NaOH to CuCl2 volume ratio, in which OLA serves not only as the structure-directing agent, but also as a weak base agent to produce hydroxyl anions. The electrochemical performances of the as-synthesized different products for sensing nitrite oxidation are evaluated. The results reveal that the electrocatalytic activity is related to the secondary nanostructures. Compared to the others, the bowknot-shaped and sphere-shaped CuO products exhibit excellent electrocatalytic activity toward nitrite oxidation and fast current response in nitrite sensing because of their peculiar hierarchical structures with high BET surface areas and well-ordered pores.

Synthesis and Characterizations of Copper Oxide Nanoparticles Within Zeolite Y

Copper oxide nanoparticles within zeolite Y have been synthesized by a procedure comprising (i) ion-exchange of copper ions into the zeolite, (ii) precipitation of copper ions with sodium hydroxide within the supercages of the zeolite, and (iii) calcination. The products were characterized by X-ray diffraction, scanning electron microscope, energy-dispersive X-ray spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The particle size of CuO products are 20 nm.

Porous CuO superstructure: Precursor-mediated fabrication, gas sensing and photocatalytic properties

A facile route was developed for the large-scale preparation of porous CuO superstructures based on a hydrothermal route with subsequent calcination. The CuO superstructures show “box-like” shape and are composed of microplatelets with high porosity resulting from the thermal decomposition of the precursor. X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform spectroscopy (FT-IR) and Brunauer–Emmett–Teller N2 adsorption–desorption analyses were employed to characterize the microstructure, size and crystalline phase of the porous cupric oxide product. The porous CuO superstructures with pore size of about 20nm have a surface area of 18.2m2/g. The gas-sensing measurements of the porous CuO superstructures demonstrate that the obtained CuO product exhibits higher sensing response to ethanol, propanol and acetone than commercial CuO powder. In addition, the enhanced photocatalytic activity of the porous CuO superstructures was also demonstrated with the photocatalytic degradation of methylene blue as a probe reaction. It is believed that the enhanced gas-sensing and catalytic properties are originated from their unique openly porous microstructure, which is highly beneficial to the reagent diffusion and mass transportation.

Tailoring CuO nanostructures for enhanced photocatalytic property

We report on one-pot synthesis of various morphologies of CuO nanostructures. PEG200 as a structure directing reagent under the synergism of alkalinity by hydrothermal method has been employed to tailor the morphology of CuO nanostructures. The CuO products have been characterized by XRD, SEM, and TEM. The morphologies of the CuO nanostructures can be tuned from 1D (nanoseeds, nanoribbons) to 2D (nanoleaves) and to 3D (shuttle-like, shrimp-like, and nanoflowers) by changing the volume of PEG200 and the alkalinity in the reaction system. At neutral and relatively low alkalinity (OH−/Cu2+≤3), the addition of PEG200 can strongly influence the morphologies of the CuO nanostructures. At high alkalinity (OH−/Cu2+≥4), PEG200 has no influence on the morphology of the CuO nanostructure. The different morphologies of the CuO nanostructures have been used for the photodecomposition of the pollutant rhodamine B (RhB) in water. The photocatalytic activity has been correlated with the different nanostructures of CuO. The 1D CuO nanoribbons exhibit the best performance on the RhB photodecomposition because of the exposed high surface energy {−121} crystal plane. The photocatalytic results show that the high energy surface planes of the CuO nanostructures mostly affect the photocatalytic activity rather than the morphology of the CuO nanostructures. Our synthesis method also shows it is possible to control the morphologies of nanostructures in a simple way.